Grinding mill



Feb. 14, 1929. 1,659,499

I J. B. SEDBERRY GRINDING HILL Filed April 4. 1924 2 Sheets-Sheet 1 WITNESSES INVENTOR @r4w 7. .B. Sadie? ATTORNEYS Feb. 14, 1928. 1,659,499

J. B. SEDBERRY GRINDING MILL Filed April 4, 1924 2 .Sheqts-Sheet 2 WITNESSES IN VENTOR 77am J13. Secberr ATTORNEYS Patented Feb. 14, 1928.

JAMES BERNARD SEDBEB BY, OI UTIGA, NEW YORK.

aamnmo MILL.

Application filed April 4, 1924. Serial 170. 704,223.

My present invention relates generally to grinders for general use in reducing materials, and more particularly to a grinding mill whose object is the elimination of certain disadvantages incident to grinding mills of similar type now in use.

It is a well known fact that grinding mills of that type employin a rotatable support around which a peripheral series of jointed or pivotal handles are disposed, for

is greatly curtaile c Other disadvantages of the usual grind ing mill arise from the quick wear of the hammers and the lack of provision for long-v er life thereof and of the pins or like members which serve as their pivotal supports, all of which my invention seeks to improve not only by a novel arrangement of the hammers relative to the cylindrical support thereof, but a novel construction of the hammers themselves and a novel manner of pivotally connecting the hammers to their supporting cylinder whereby to avoid the necessity of inserting new parts except at long intervals in the life of the mill.-

Thus my invention aims to improve the usual mill in respect tothe eflectiveness and efliciency thereof in its ordinar use and also aims to greatly prolong the e ective life of its grindin parts and at the same time materially re uce the cost of upkeep without material increase in the initial cost.

A still further object of my invention is to provide novel discharge means for the ground material so as to avoid the necessity for the amount of power usually required to withdraw such material by suction from the machine and force the same by blast to a distant point.

In the accompanying drawings which illustrate my invention and form a part or this specificati' 11,

Figure 1 is) a vertical transverse section taken-through my improved grindin mill substantially in the plane of the grinding shaft and showing the grinding cylinder in elevation,

Figure 2 is a central longitudinal section taken through the mill,

Figure 3 is a detail section through a poation of the hammer supporting cylinder, an

Figures 4 and 5 are detail perspective views of hammers utilized in the mill, Figure 5 illustrating a slightly modified form with respect to Figure 4 as well as Figures 1 and 2.

Referring now to these figures my invent1on aims to improve that type of'grinding mill wherein the grinding member in: the form of a cylinder generally indicated at 10 in Figure 2 is disposed within a housing generally indicated at 11 into which the material to be ground is fed upon an inclined feed table 12, the cylinder 10 being disposed within a substantially cylindrical portion of the housing 11 above a semicyllndrical screen 13 "through which the ground material is forced directly into a lower transverse feed trough 14' as well as upon oppositely disposed inclined feed boards 15 whose lower ends connect with the side of the feed trough 14.

In accordance with my invention the grinding cylinder is made up of a series of disks-16 of similar size disposed in spaced relation upon the squared portion 17 of the grinding shaft 18, the latter of which has a pulley 19 externally of the casing ll belt connected in practice to any suitable source of power. The disks 16 making up the cylinder are spaced apart by spacing members 20 around the grinding shaft at the center of the disks, and adjacent to their peripheral edges the several disks of the series are connected by a circumferential series of hammer supporting bolts 21, the ends of which have suitably locked nuts thereon as seen at 22 in Figure 1 whereby the bolts maybe removed whenever desired.

The hammers according to my present invention are each formed of a slngle piece of material of generally oblong form and each have a longitudinal slot so that while held in radially outstanding position by centrifugal force during operation, they are free to reverse themselves endwise with respect to the cylinder whenever the latter is stopped and started. These hammers, indicated at 23, whose slots are seen at 24, may be either finished with square out ends formdisks 16 .of the cylinder and according to my present invention they are arran ed along V-shaped lines around the cylin er, starting with a pair of hammers arranged side byside at the center of the cylinder 1 and comprising two series of hammers on each bolt 21 which gradually diverge as they progress around the cylinder, toward the 0pposite ends of the cylinder as plainly seen in Figure 1, that is, the hammers on each succeeding hammer bolt converge from either side to a common center point, thus forming a flying wedge of hammers arranged in a V- sha e.

'l he effect of this is, as the cylinder revolves, material is gathered towards center by the action of the hammers spaced closer and closer together. Then when the two center hammers reach it, the material is scattered over the cylinder again; this action is repeated from 2500 to 3000 times per minute; the battery of hammers revolving at high speed keeps the material in suspension and vibrating back and forth over the entire flyirg wall of cutting, grinding and smashing e es.

The hammer acts just like an oar drawn through the water; it throws feed outwardly and owing to the peculiar manner in whic the two hammers are placed most of the feed goes to the center of the mill at all times.

I thus avoid the parallel arrangement of the hammers in longitudinal rows and avoid the known disadvantage incident to such a construction as first above noted by insuring movement of the material being ground, from.

one end of the cylinder to the other during the grinding operation and by the construction of the several hammers, each of a single piece of material, I clearly avoid the numerous parts making up the hammers in the ordinary construction where each hammer is rotatable at and between the outer ends of a pair of hammer arms the latter of which are pivotally connected at their inner ends to the d'sks making up the cylinder.

'It is moreover true that the major ortion of the wear falls upon the cutting edges of the hammers themselves and upon their pivotal connections with the cylinder. According to my present construction each hammer is itself reversible so as to bring into action one side of each end thereof and may then be turned around to present the other side of each end before it is necessary to renew the hammers, The hammers having the elongated slot and being of much greater length than width and increased weight produces a greater centrifugal outward force, together with an increased resistance to backward deflection, due to a tangential force caused by the operation of the working section of the hammer in connection with the material being ground; this is an advantageous construction and arrangement of the hammers. By virtue of the fact that there are only two hammers according to my present arrangement, in connection with each hammer supportingbolt 21, only two portions of these olts will be subject to wear at the same time and when such parts of the several bolts have become considerably worn it is simply necessary to remove the same and advance the two helically disposed series of hammers the distance of one of the bolts in order that the same arrangements may be preserved and the hammers at the same time enga ed with the unworn portions of the bolts. t is obvious that this may be accomplished half as many times as there are spaces on the bolts between the disks of the cylinder and may be easily and quickly effected by simply raising the upper portion of the casing or housing and successivel removing and replacing the hammer pivot olts 21. y

In the respects thus mentioned my invention obviously provides for more effective action in so far as reduction of material is concerned and also for reater durability and substantially longer% the parts together with increased capabilities in so far as interchange and removal of the parts is concerned.

My invention is also directed in part to the means for withdrawing the ground material falling through the screen 13 into the trough 14 and proposes the use of a discharge shaft 27 extending lengthwise through the trough as clearly seen in Figures 1 and 2. This shaft is mounted in bearings 28 and is provided at one end with a stepped pulley 29 adapted to be belt connected by means of a belt 30 with one stepped end 31 of the driving pulley 19 before mentioned. Within the troughl l: the dischar e shaft 27 has a series of vanes 32 so pitche as to urge movement of the material within the trough toward one end of the said trough where the latter 0 ens into a casing 33 having an upper disc argle opening 34. Within this casin 33 the s aft 27 has what ma be termed a eater wheel as distinguished mm the ordinary fan of a blower, this wheel indicated at 35 being designed to take the material received from the trough 14 and throyx the same upwardly out of the discharge opening 34 by Its own impactwith the material as ife of certain of distinguished from the action of the usual blower wherein the material is discharged alon with a blast of air and a separator is required at a distant point. In the action of the present discharge means material is not drawn into the casing 33 by suction but by virtue of the mechanical action of the pushin vanes 32 and in order to regulate the v0 ume of material passing from the trough 14 into'the casing 33 and thus avoid spasmodic action of the beater wheel 35, a vertically shiftable damper or cut oil 36 may be manually adjustable within that end of the trough 14: immediately adjacent to the casing 33. The other end of the trough 14 is normally closed by a closure plate 37 and this plate is preferably made removable so that it may be displaced in the event it is desired to substitute a blower fan for the beater wheel in instances where it is desired to discharge the. material at a considerable distance from the grinding mill.

With the present discharge apparatus, however, the cost of the o eration is reduced to a minimum, considerably less power being required for the driving of the beater wheel :5 than is necessary with the usual blower I claim: t

1. A' grinding mi'll including a shaft with a grinding cylinder mounted thereon and constructed of a series of discs of similar size in spaced relation, said discs being held against turning on said shaft, a circumferen tial series of hammer supporting bolts connecting said discs adjacent the peripheral edges thereof, hammers having elongated slots said bolts extending through said slots whereby said hammers are held in radially outstanding position by centrifugal force during operation and thereby adapted to automatically reverse themselves endwise with respect to the cylinder on the stopping and starting of the cylinder.

2. In a grinding mill a hammer su porting cylinder including a central shaft and having a circumferential series of hammer supporting bolts paralleling the axis of r0- tation of said support, and endwise automatically reversible hammers of fiat elongated form having lengthwise slots through which said bolts extend whereby to pivotally connect the hammers to the support and guide and provide for their endwise reversal when in action, each of said hammers being in a single piece.

3. In a grinding mill, in combination a hammer support comprising a central shaft, a longitudinal series of disks spaced from one another and secured to said shaft,a series of hammer supporting bolts within the periphery of the disks and parallel to the shafts and extending through the disks, and slotted hammers movably mounted on said bolts and automatically shiftable by centrifugal force to opposite ends of the slots in said hammers, whereby to reverse themselves said hammers being arranged in pairs in single helical lines from a common center'of the support and diverging from said center to the outer edges of the support, whereby to form a V-shaped rotor, to scatter material over the support.

4. A hammer for grinding mills of the class described comprising an elongated plate, said plate having an elongated continuous slot, and symmetrical about the longitudinal and transverse axes, for the purpose set forth.

J AJWES BERNARD SEDBERRY. 

